JOHNSTON ROAD LAND USE STUDY

Transcription

1 JOHNSTON ROAD LAND USE STUDY SERVICING FEASIBILITY STUDY Project No Prepared for: City of Ottawa Planning Branch Infrastructure Approvals Branch Prepared by: David McManus Engineering Ltd Camelot Drive Nepean, Ontario K2G 5X8 December 2009

2 TABLE OF CONTENTS 1.0 INTRODUCTION SANITARY SEWAGE SERVICING STORM DRAINAGE AND STORMWATER MANAGEMENT Storm Drainage Stormwater Management WATER SERVICING RECOMMENDATIONS CONCLUSIONS FIGURES Figure 1 Study Area Limits Figure 2 Concept plan Figure 3 Existing Sanitary Infrastructure Figure 4 Conceptual Sanitary Infrastructure and Sanitary Drainage Areas Figure 5 Existing Storm Infrastructure Figure 6 Conceptual Storm Infrastructure and Storm Drainage Areas Figure 7 Existing SWM Infrastructure and Drainage Areas Figure 8 Existing Water Infrastructure Figure 9 Conceptual Water Infrastructure TABLES Table 1 - Existing Sanitary Sewer Infrastructure Adjacent to JRLUS Table 2 - Sanitary Sewer Servicing Constraints Table 3 - Existing Storm Sewer Infrastructure Adjacent to JRLUS Table 4 - Storm Sewer Servicing Constraints Table 5 - Existing Water Infrastructure Adjacent to JRLUS Table 6 Water Servicing Constraints APPENDICES Appendix A Conceptual Sanitary Sewer Design Calculations Conceptual Easement Width Calculations Appendix B Conceptual Storm Sewer Design Calculations Storm Drainage Area Plan (provided by City) Oct Conroy Road Swamp Surface Drainage Area Patterns drawing

3 Johnston Road Land Use Study Servicing Feasibility Study 1.0 INTRODUCTION David McManus Engineering Ltd. (DME) has been appointed by the City of Ottawa to provide a high level servicing feasibility analysis for the Johnston Road Land Use Study (JRLUS) area. The approximately 118 ha subject property is currently located inside the urban development boundary of the City of Ottawa and is bounded by Albion Road to the west, Johnston Road to the south, Conroy Road to the east and an existing hydro corridor (approximately 0.6 km south of Walkley Road) to the north (see Figure 1 Study Area Limits). The intent of this report will be to highlight the opportunities and constraints in providing municipal servicing (sanitary sewers, storm sewers, stormwater management and, watermains) to the subject lands based on the availability (proximity, capacity, etc.) of those services. The servicing feasibility analysis for the JRLUS has been based on the preferred land use Concept Plan (herein called the Concept Plan) developed as part of a City initiated Phase 1 and Phase 2 Class Environmental Assessment process (see Figure 2 - Concept Plan). The Land Use Study and Class EA process were carried out concurrently with a Transportation Study. An Existing (Servicing) Conditions analysis, Geotechnical investigation and ESA were also conducted to support the overall study initiative. The Concept Plan was one of three concepts initially developed by City of Ottawa Planning Staff and presented to the public for input at a public open house held in June Based on the input gathered from the land use study, June 2009 open house and input from a subsequent meeting with the JRLUS landowners, Concept C was selected as the preferred concept but was also revised to include a preferred road configuration. The current JRLUS area land use is made up of an existing snow dump, CN and CP railway lands, small pockets of industrial development, a skateboard park, a City owned water tower, the Greater Turtle Natural Area candidate ESA (GTNA) and undeveloped land. Existing topography appears to direct drainage south easterly for a majority of the site and ultimately to McEwan Creek while a small portion (approximately the westerly ¼ portion of the JRLUS area) drains westerly and ultimately to Sawmill Creek. DME Project No Page 1 December 2009

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6 Johnston Road Land Use Study Servicing Feasibility Study Based on the Concept Plan and the existing land uses which are to remain unchanged (water tower, snow dump, CN rail line, GTNA), the surrounding existing municipal infrastructure will generally need to service approximately 5 ha residential, 43 ha light industrial, 1.1 ha office, 15.2 ha commercial as well as a future City of Ottawa works yard. 2.0 SANITARY SEWAGE SERVICING As outlined previously in the JRLUS Existing Conditions Report (prepared by David McManus Engineering Ltd., revised February 2009), details regarding the existing sanitary sewer infrastructure found adjacent to the study lands were provided (see Figure 3 Existing Sanitary Infrastructure). Those details, for sake of comprehensiveness, have been summarized below: Table 1 - Existing Sanitary Sewer Infrastructure Adjacent to JRLUS Location Diameter (mm) Available Capacity (L/s) (1) Depth to Services (m) (4) South Ottawa northern JRLUS boundary ,000 (2) Collector Trunk (approximately south of the sewer existing Hydro corridor) Green Creek Collector Trunk sewer southern JRLUS boundary (partially within the Johnston Road ROW) (3) Albion Road sewer western JRLUS boundary 450 unknown 4.5 Notes: * No sanitary sewer appears to exist within the Conroy Road ROW (i.e. eastern JRLUS boundary) (1) High level flow/capacity assessment of the main trunk sewers in the vicinity of the JRLUS (provided by City staff) (2) Currently conveys a discharge of ~ 4,800 L/s but has a capacity in the order of 10,800 L/s (as per City staff) (3) Currently conveys a discharge of 340 L/s (east of Albion Road) but has a capacity in the order of 860 L/s (as per City staff) (4) Approximate depth to invert(s) DME Project No Page 2 December 2009

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8 Johnston Road Land Use Study Servicing Feasibility Study Based on the Concept Plan and a high level sanitary drainage area plan (previously provided by City Staff), the onsite sewage can be conveyed to the existing adjacent servicing infrastructure (see Figure 4 Conceptual Sanitary Infrastructure and Sanitary Drainage Areas) in the following manner: A 250 mm diameter sanitary sewer within the ROW of the proposed street located in the south-western portion of the JRLUS area. A 250 mm diameter sanitary sewer within the ROW of the proposed street located in the south-eastern portion of the JRLUS area. This sewer then connects to the existing Green Creek Collector via a 250 mm diameter sanitary sewer within an approximately 16 metre wide easement (due to depth of the cross-section and subject to final design, see Appendix A). A 250 mm diameter sanitary sewer within the ROW of the proposed street within the northern portion of the JRLUS area. This sewer then connects to the existing South Ottawa Collector via an existing sanitary access structure (located at the NE corner of the JRLUS area). It should be noted that a minimum 250 mm diameter sanitary sewer will be required to service the site as per current City standard for industrial/commercial developments. A conceptual sanitary sewer design sheet has been provided in Appendix A that demonstrates that a 250 mm diameter sewer at approximately minimum grade has sufficient capacity to service the JRLUS as proposed in the Concept Plan. It is anticipated that total flows for the JRLUS area will be 30 L/s. The flows, while felt to be conservative, are based on planning level information only. Given the unused/excess capacity identified in Table 1 above (i.e. South Ottawa and Green Creek Collectors only), there is available capacity in the adjacent existing trunk sewer infrastructure to incorporate the additional flows from the JRLUS area with no future capacity constraints anticipated. The calculations that were prepared as part of this high level analysis assume that the R.O. Pickerd Wastewater Treatment Plant will have enough reserve capacity to accommodate the proposed development of the JRLUS area (as per the land use identified on the Concept Plan). It is recommended, however, that the reserve capacity of the treatment plant be verified as development of the JRLUS area commences. DME Project No Page 3 December 2009

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10 Johnston Road Land Use Study Servicing Feasibility Study The following servicing constraints, previously identified, will also have to be taken into account once development commences: Table 2 Sanitary Servicing Constraints Constraints During a review of the background information, poor soils conditions were encountered during construction of the existing servicing infrastructure. It is recommended that a more detailed soils investigation be completed as part of the future work. This work should include the identification of grade raise restrictions, recommendations for foundation depths, groundwater table identification and any special provisions to servicing infrastructure (i.e. service locations, depths, materials, and construction techniques, etc.). Some of the existing sanitary trunk sewer infrastructure is located at large depths which may require high level services and minimization of connection points. Specifically, the South Ottawa Collector is excessively deep and requires further investigation to determine if high level sewer connections can be made economically or can be made to the existing on-site structures/chambers. High water table and Leda clay concerns may require clay dikes in sewer service trenches to prevent draw down of groundwater. This will be subject to the recommendations determined as part of any future detailed geotechnical investigations. The following additional analyses of the downstream receiving trunk sewer should be completed during either prior to commencement of development or as part of the detailed Master Servicing design of the future development: Confirmation of downstream capacity, downstream surcharging issues, need for any upsizing of downstream sanitary trunk sewers or any other downstream infrastructure improvements infiltration rates via monitoring 3.0 STORM DRAINAGE AND STORMWATER MANAGEMENT 3.1 Storm Drainage Similar to the work completed on the existing sanitary sewer infrastructure, the Existing Conditions Report also identified details regarding the existing storm infrastructure found adjacent to the study lands. These details are summarized in Table 3 below and are shown on Figure 5 Existing Storm Infrastructure. DME Project No Page 4 December 2009

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12 Johnston Road Land Use Study Servicing Feasibility Study Table 3 - Existing Storm Sewer Infrastructure Adjacent to JRLUS Location Diameter (mm) Available Capacity (L/s) (1) On-site storm north-west quadrant of the 1650 unknown 5 sewer JRLUS Depth to Services (m) (2) Eastern Community Storm Trunk sewer southern JRLUS boundary (partially within the Johnston Road ROW from Tapiola Crescent to Conroy Road) 2700 unknown 5-7 Conroy Road ROW Conroy Road ROW (high level) Albion Road ROW Albion Road ROW Notes: eastern JRLUS boundary (western edge of the Conroy Road ROW at rail line) eastern JRLUS boundary (westerly and easterly portion of the Conroy Road ROW) north western JRLUS boundary (sewers do not connect through the rail line with the storm sewers in the southern portion of Albion Road but outlet to an open ditch running westerly) south western JRLUS boundary (storm sewer connects to a 1050mm diameter storm sewer which runs westerly from the Albion and Johnston Road intersection) 2250 unknown unknown unknown unknown (1) Information pertaining to a high level understanding of the capacity and the risk of surcharge of the main trunk sewers in the vicinity of the JRL was not available from City staff. (2) Approximate depth to invert(s) DME Project No Page 5 December 2009

13 Johnston Road Land Use Study Servicing Feasibility Study Based on the Concept Plan and a high level storm drainage area plan (previously provided by City Staff and a copy provided in Appendix B), the surface flows generated onsite can be conveyed to the existing adjacent servicing infrastructure (see Figure 6 Conceptual Storm Infrastructure and Storm Drainage Areas) in the following manner: A 1500 mm diameter storm sewer within the ROW of the proposed street located in the south-western portion of the JRLUS area which will drain to the Sawmill Creek Subwatershed. The north-western portion of the JRLUS area will drain to the Sawmill Creek Subwatershed via an existing 1650 mm diameter storm sewer. Storm sewers ranging from 300 to 1650 mm within the ROW of the proposed street located in the mid-northern and north-eastern portion of the JRLUS area. The size of the existing culvert underneath the rail tracks is unknown at this point and will need to be determined through site investigations (may cause restriction/backwater of flow if smaller than storm sewer sizing). Storm sewers ranging from 300 to 1950 mm in diameter within the ROW of the proposed street located in the mid-southern and south-eastern portion of the JRLUS area. This area will drain to a proposed 16 m wide easement and ultimately McEwan Creek via a connection to the existing 2700 mm diameter trunk sewer at the southern JRLUS boundary. City staff have not been able to provide details regarding the available capacity of the existing storm infrastructure or an understanding of the risk of surcharge of the main storm trunk sewers in the vicinity of the JRLUS. However, it has been assumed that capacity is available to service the JRLUS area and a conceptual storm sewer design sheet has been provided in Appendix B. It is anticipated that total flows will be ~ 15,500 L/s from the JRLUS area to McEwan Creek Subwatershed and will be ~ 5,700 L/s from the JRLUS area to the Sawmill Creek Subwatershed. The flows are based on planning level information only and should be verified at a more detailed design stage. As with the watermain and sanitary servicing assessments of existing conditions, a review of the opportunities and constraints to development of the JRLUS (from a storm and stormwater management infrastructure servicing perspective) was also completed. The following opportunities and constraints were felt to be applicable: DME Project No Page 6 December 2009

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15 Johnston Road Land Use Study Servicing Feasibility Study Table 4 Storm Sewer Servicing Constraints Constraints During a review of the background information provided by the City, poor soils conditions were encountered in the area during construction of the various existing servicing infrastructure. It recommended that a more detailed soils investigation be completed as part of the future work. This work should include the identification of: grade raise restrictions, recommendations for foundation depths (as it applies to the storm services), groundwater table identification and any special provisions to servicing infrastructure (i.e. service locations, depths, materials, and construction techniques, etc.). Greater Turtle Natural Area (GTNA) is identified as a candidate Environmentally Sensitive Area (ESA). Given the need to maintain surface water and groundwater contributions to the Greater Turtle Natural Area (GTNA), further hydrogeological studies are recommended. Specifically, the studies should investigate the impact of development from the JRLUS area as whole on the GTNA. This in turn may impact the type of stormwater management required (i.e. infiltrative measures rather than end-of-pipe, etc.).water balance calculations should be included, as well as maintaining the existing drainage patterns to/from this area. Lastly, any environmental concerns of the GTNA as it relates to servicing should also be addressed with further studies. Some of the existing sewer infrastructure is located at deeper depths. High level services may be required as well as minimization/optimization of the number of connection points to the deep sewer. High water table and Leda clay concerns may require clay dikes in sewer service trenches to prevent draw down of groundwater. This will be subject to the recommendations determined as part of any future detailed geotechnical investigations. 3.2 Stormwater Management In addition to outlining the existing storm infrastructure, the Existing Conditions Report identified the following two SWM facilities (see Figure 7 Existing SWM Infrastructure and Drainage Areas) in the vicinity of the JRLUS: Approximately northwest of the site in the vicinity of the Albion Road and Kitchener Avenue intersection. Generally located in the north east quadrant of the JRLUS boundary within the City of Ottawa snow dump area. Further investigation regarding these and any other existing stormwater management facilities should be completed in the future. As outlined in the preceding section (Section 3.1 Storm Drainage), City staff have been unable to provide details regarding the available capacity of the existing storm DME Project No Page 7 December 2009

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17 Johnston Road Land Use Study Servicing Feasibility Study infrastructure or an understanding of the risk of surcharge of the main trunk sewers in the vicinity of the JRLUS. However, as per details provided in the (yet to be approved) McEwan Creek Water Quality and Erosion Control Study (McEwan Report), a downstream stormwater management facility to service the lands located within the McEwan Creek subwatershed boundary (which includes the JRLUS area) was recommended. In the absence of approval of this report, or if construction of the JRLUS area precedes construction of the proposed pond(s), or if density for the JRLUS is greater than what is accounted for in the McEwan Report, on-site controls will be required. These controls should be in keeping with the following SWM recommendations which were provided as the basis for the pond design in the McEwan Report: 60% TSS removal Attenuation of peak flows to the 2 year pre-development level for all storms up to and including the 100 year return period storm Maintain temperature variations similar to those currently experienced in McEwan Creek The portion of the JRLUS area tributary to Sawmill Creek Watershed should be in keeping with the recommendations outlined in any governing subwatershed report (if in existence) prepared for that watershed. As a minimum, however, the following on-site controls should be provided: Attenuation of peak flows to the 2 year pre-development level for all storms up to and including the 100 year return period storm??% TSS removal In addition to the off-site controls, the on-site stormwater management controls for the JRLUS area should incorporate the following features: Roof leaders directed to grassed areas and/or rooftop storage (where available) Identification of minor system, major system, HGL and overland flow routes. Swales and ditch-inlet catchbasins to collect runoff from undeveloped adjacent areas Inlet control devices in the parking lot catch basins to provide parking lot storage and potentially reduce the required size of the downstream stormwater management pond(s) Preservation of the pre-development drainage boundaries between the McEwan Creek and Sawmill Creek subwatersheds as much as possible. DME Project No Page 8 December 2009

18 Johnston Road Land Use Study Servicing Feasibility Study Maintain the water contribution via surface and groundwater drainage to the GTNA candidate ESA (see Appendix B for October 1994 Conroy Road Swamp Surface Drainage Area Patterns drawing). 4.0 WATER SERVICING As part of the work completed for the Existing Conditions Report, details regarding the existing water infrastructure found adjacent to the study lands were provided. In addition, City staff had confirmed that the JRLUS area is within the 2C pressure zone. The existing infrastructure details are summarized below and are shown on Figure 8 Existing Water Infrastructure. Table 5 - Existing Water Infrastructure Adjacent to JRLUS To City owned snow dump from Conroy Road ROW Location Westerly from Conroy Road to the existing Conroy Road elevated water tank (northeast quadrant of the study area) Diameter Depth to (mm) Services (m) (4) Johnston Road ROW (1) southern JRLUS boundary (partially within the Johnston Road ROW) Albion Road ROW Johnston Road western JRLUS boundary (crosses under the existing rail line) southern JRLUS boundary (~ at the most westerly Tapiola Crescent and Johnston Road intersection) 610 unknown 300 (2) To be determined in field DME Project No Page 9 December 2009

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20 Johnston Road Land Use Study Servicing Feasibility Study Johnston Road Albion Road ROW southern JRLUS boundary (~ at the easterly Tapiola Crescent and Johnston Road intersection) western JRLUS boundary (runs southerly along the Albion Road ROW and then turns easterly, before the rail line, to mid way between Albion and Conroy Road) (3) 200 (2) To be determined in field 150 unknown Conroy Road ROW eastern JRLUS boundary Notes: (1) A portion of this watermain (~ 740 metres between Tapiola and Tapiola) is presently out of service. As per City Staff, the watermain cannot be repaired but will need to be replaced which is currently scheduled for sometime in (2) Watermain stub(s) which may exist on the north side of the Johnston Road ROW (verification of the existence of these watermain stubs will need to be verified via field investigations at a later date) (3) To service three buildings in the northwest quadrant of the study area (4) Approximate depth to top of watermain In terms of the adequacy of water pressure for the JRLUS area, City mapping indicates that for a majority of the site, adequate water pressure will be available. However, a small section (north-west quadrant of the site) may encounter less than ideal water pressure. This will have to be confirmed and any mitigative measures will need to be prescribed once a detailed water model (based on detailed grading and geotechnical design) has been completed. Assuming that adequate water pressure is available for the JRLUS area, water servicing, based on the Concept Plan, can be provided via connections to the following existing water servicing infrastructure (see Figure 9 Conceptual Water Infrastructure): A 300 mm diameter watermain within the ROW of the proposed street located in the southern portion of the JRLUS area which should connect to the existing watermains within the Albion and Conroy Road ROWs. DME Project No Page 10 December 2009

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22 Johnston Road Land Use Study Servicing Feasibility Study A 300 mm diameter watermain within the ROW of the proposed street within the northern portion of the JRLUS area which should connect to the existing watermains within the Albion and Conroy Road ROWs. It should be noted that a minimum 300 mm diameter watermain will be required to service the site as per current City standards for industrial/commercial developments. The following servicing constraints, previously identified as part of the Existing Conditions analysis, will also have to be taken into account once development commences: Table 6 Water Servicing Constraints Constraints Soil and water table issues may impact service locations, depths, and construction techniques. In addition, City staff have indicated that corrosive soils have been encountered along the southern JRLUS boundary. This will dictate the type of watermain pipe and appurtenance material to be used. North-east portion of site is a considerable distance from the nearest existing watermain. A connection to the 600 mm diameter feeder main from the on-site elevated storage tank is not recommended or currently endorsed by City staff. Slight pressure concerns exist in the developed area to the north-west of the study area. A detailed water modelling analysis will need to be completed to determine if adequate water pressure can be provided for the entire study area. Other required infrastructure improvements within this pressure district are uncertain at this point High water table and Leda clay concerns may require clay dikes in sewer service trenches to prevent draw down of groundwater. This will be subject to the recommendations determined as part of any future detailed geotechnical investigations. In addition to examining the above noted constraints in more detail at a later design stage, the following further detailed water servicing analyses will also need to be completed: 2C Pressure Zone infrastructure improvements, if any, to allow for the JRLUS area to be adequately serviced. completion of a thorough modelling analysis of capacity of the water supply to: ensure that adequate pressure (including fire flow requirements) can be provided Identify limitations to the provision of adequate water service to the subject lands DME Project No Page 11 December 2009

23 Johnston Road Land Use Study Servicing Feasibility Study identification of opportunities for system looping to provide redundancy and to meet water quality objectives mitigative measures, if required, for adjacent areas that may experience less than ideal water pressure as a result of the new service demands form the JRLUS area 5.0 RECOMMENDATIONS It is recommended that, prior to any development of the JRLUS area proceeding, the following tasks be completed to confirm the servicing feasibility of the entire JRLUS area lands: Preparation of a Master Servicing Study for the complete study area outlining servicing recommendations/solutions including known Stormwater Management Requirements, possible SWM facility locations or treatment train options. Existing services (sanitary and storm) are deep (varies from 5 metres to 25 metres) and it is anticipated that a high level strategy will be required. The study should circumvent any servicing constraints that may surface if development was to proceed in a piecemeal fashion. This will also allow future development to determine/confirm their flows with detailed calculations part of the individual design process. Retention of a Hydrogeological and Environmental Consultant in order to complete a comprehensive water balance model (as it pertains to the impact on the Greater Turtle Natural Area). In addition, the Geotechnical investigation has recommended that site specific hydrogeological investigations will be required for individual, proposed developments to protect both the proposed developments and the surrounding properties from ground water lowering and settlement of the soils. Confirmation of the existing water system s ability to provide adequate pressure and fire flows to the area via preparation of a water model. Preparation of Site specific geotechnical investigations are recommended for individual, proposed developments to address the existing soil conditions present throughout the study area as it relates to the impact the future servicing infrastructure. DME Project No Page 12 December 2009

24 Johnston Road Land Use Study Servicing Feasibility Study 6.0 CONCLUSIONS This Servicing Feasibility Report has been prepared to demonstrate that servicing connections to the existing municipal water, sanitary and storm sewer infrastructure can be provided to municipally service the lands found within the JRLUS area. This servicing analysis has been based on the preferred Concept Plan developed during a City initiated Phase 1 and Phase 2 Class Environmental Assessment process. Capacity issues, where they are currently known, have been indentified as well as any additional constraints to development that require further study. An overall Master Servicing Study is recommended to be completed prior to commencement of development so that any issues can be resolved for the JRLUS area to understand potential impacts to upstream and downstream infrastructure as a whole, rather than allowing development to proceed in a piecemeal fashion and potentially encountering difficult servicing problems in the future. Prepared by: David McManus Engineering Ltd. Reviewed by: David McManus Engineering Ltd. Angela H. Jonkman, P. Eng. Project Manager Michael Keating, P.Eng. Senior Project Manager DME Project No Page 13 December 2009

25 Johnston Road Land Use Study Servicing Feasibility Study APPENDIX A CONCEPTUAL SANITARY SEWER DESIGN CALCULATIONS CONCEPTUAL EASEMENT WIDTH CALCULATIONS

26 SANITARY SEWER CALCULATIONS FOR JRLUS PROJECT: /18/2009 DME LTD. LOCATION Residential Population Light Industrial Heavy Industrial Commercial CUMMULATIVE Resid. PEAKING PEAK EXTRAN. PEAK PEAK PROPOSED SEWER DATA EXCESS (Ha) Flow Accu. Area Flow Accu. Area Flow Accu. Area POP. FACTOR POP. GROSS EXTRAN. DESIGN LENGTH PIPE GRADE CAPACITY VELOCITY CAPACITY % FULL L/s (Ha) L/s (Ha) L/s (Ha) M FLOW (l/s) AREA (Ha) FLOW (l/s) FLOW (l/s) (m) SIZE (mm) (%) (l/s) (m/s) (l/s) Northern Section Area % Area * * * * * * Southern Section Area % Area % Easement % TOTAL Notes: * Existing 1650 mm diamater sanitary sewer Population = 60 persons/ha undeveloped residential = 3.4 persons/unit for single = 2.7 persons/unit for townhouse units and semi-detached family units = 1.8 persons/unit for apartments Peaking Factor = /(4 + (P)^0.5 P = Population in 1000's Peak Population Flow (l/s) = Cummulative Population (persons) x 350 l/person/day x Peaking Factor / sec/day Light Industrial Avg. Flow (l/s) = Gross Area (ha) x 35,000 l/gross ha/d x peaking factor / sec/day Peaking factor = per Figure in Appendix 4-B in City of Ottawa Sewer Design Guidelines Heavy Industrial Avg. Flow (l/s) = Gross Area (ha) x 55,000 l/gross ha/d x peaking factor / sec/day Commercial Avg. Flow (l/s) = Gross Area (ha) x 50,000 l/gross ha/d x peaking factor / sec/day Peaking factor = 1.5 Commercial & Industrial Peak Extraneous Flow (l/hr) = pipe leakage = 0.28 l/s/effective gross ha Peak Design Flow (l/s) = Peak Population Flow (l/s) + Peak Extraneous Flow (l/s) Page 1

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28 Johnston Road Land Use Study Servicing Feasibility Study APPENDIX B CONCEPTUAL STORM SEWER DESIGN CALCULATIONS STORM DRAINAGE AREA PLAN (provided by City) Oct Conroy Road Swamp SURFACE DRAINAGE AREA PATTERNS drawing

29 1:50 PM 12/18/2009 DME Project: 2814 JRLUS Storm Sewer Design Sheet LOCATION Area (Ha) Flow PROPOSED SEWER TIME RAINFALL PEAK PIPE PIPE FULL FLOW TIME OF EXCESS Drainage Area R= R= R= INDIV ACCUM OF INTENSITY FLOW SIZE SLOPE LENGTH CAPACITY VELOCITY FLOW CAPACITY AR 2.78 AR CONC. I Q (l/s) (mm) (%) (m) (l/s) (m/s) (min.) (l/s) 4 (A,B,C) Culvert Easement * *1 *1 *1 *1 *1 *1 *1 1 * Notes: *1 To existing 1650 mm diameter storm sewer *2 To existing ditch system east of Albion Road

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